Islam



(No Model.) 6 Sheets-Sheet. 2.

' AS. DARLING.

COMPARATQR, No. 292.415.

auf".

N. PETERS, Phowmmwen wanlngwn. D. c.

Wiinesses 6 Sheets-Sheet 4. l S. DARLING.

COMBARATOYR.

Patented Jan. 22,

Nv Parras mmxfrlluwgmmnr. mnnl-,uml n, c

(No Model.)

6 Sheets-Sheet 5. S. DARLING.

COMPARATOR.

No 292,215. Patented JM.V 22,1884.

- Invenr:

ifnesse's s sheets-sheer by s. DARLIYNG.

GMPARATOR.

Patented Jan. 22, 1884.

PATENT Si Erica,

SAMUEL DARLING, OF PROVIDENCE; RHODE ISLAND. f4

lcowl PARATOR.

`SPECIFICA'LION forming part of Letters` Patent No. 292,415, dated January 22, 1884, Application filed March 1,1883A (No modLl.)

$ @ZZ whom, it may concern: 4

Be it known that I, SAMUEL DARLING, of Providence, Rhode Island, have invented a new and useful Improvement in Comparators for Comparing Measures of Length one with another; and I do hereby declare that the fol-, lowing, taken in connection with the drawings which'ac'company and form part of this specification, is a full, clear, and exact description of the invention, which will enable others skilled in the art to whichit appertains toA make and use the same.

The end iu view by this invention is to produce an instrument with which comparisons can be made with a greater degree of accuracy and uniformity thanhaveheretoforebeenmade, and which the advanced state of the mechani cal sciences now requires; and it consists in av comparator in which the tables that support the articles to be compared are attached toa pivoted frame, by which they can be swung back; and forth Y under the microscopes a comparator having above the .tables and swinging frame a horizontal beam to support the microscopes, a tracer, (if one be used,) a head- 4 rest, and any'apparatus that may be required to operate the microscopes and tracer, the said beam to extend the working-length of the comparator and be supported at the ends to leave'a free and open space under it for the movement of the tables and admission of light, and also tovhave on its side a shelf or bracket` to support the ways for the microscopes, and the apparatus that may be placed upon it in the luse of the comparator; a comparator having a thermometer embedded in mercury in the table or in any other part' of which it is desirable to know the exact temperature; a com-parator with longitudinal and transverse ways.- i'or the movements of the microscope, or with longitudinal, transverse, and vertical ways or guides by which the microscopes can be moved and adjusted; a comparator having a rest to steady the head when adjusting the microscopes; a comparator having abutting pieces arranged for comparing end-measure with line-measure, all of which I shall fully illustrate and describe in thefo'llowing specification. y

The great eXactness with which scales are now graduated requires a correspondingly-acout duringI the comparison.

obtain comparisons with great accuracy withcurate instrument for comparing the length of one with another, and one part with another part of the same scale. The most important features'to be obtained in a comparator are, rst, sufficient strength to prevent any bending, twisting, or yielding in any perceptible manner secondly, facilities for testing the scales as rapidly and with as little manipulation as possible; and, thirdly, devices by which the scales being compared can be alternately brought under the microscopes. with as little motion and delay as possible, after the microscopes shall have been adjusted to the scales for the purpose of testing the accuracy yof the adjustment ci the micrometcrs. But to obtain the results aimed at in this invention,with this or any comparator, the measures to be tested must be of a uniform temperature during the process, and to insure that, it will be necessary that the measures to be compared and the comparator be of the same temperature throughout having the temperature uniform would be fatal to the operation. The temperature may rbe regulated by the use of a blower, as shown in Patent No. 227,962, May 25, 1880.

An attempt t0 I have described and illustrated one method of constructing and operating my improved comparator in the drawings, of which the upper part of Figure l is a full front view of the comparator, and the lower part is a longitudinal section (C D, Fig. 2) through the middle of the main frame-work. Fig. 2 is a crosssection; of the comparator at A B, Fig. l, the

part tothe right of the cutting-plauebeing supposed to be removed; Fig.. 3, plan or top view ofthe comparator, drawn to a larger scale than Figs. 1 and 2.A Fig. tvis a horizontal section through E F, Fig. 1, showing the arrangement ofthe gearing, which will be more fully Adescribed hereinafter. The remainder of the drawings-illustrate details of construc-v tion and methods of operation, and will be explained in turn under those headings.

The frame of the comparator consists of four Apieces of cast-iron. (Shown in Figs. 1, 2, and 3.)

Gis the base, having a heavy rib, H, proj ecting Iupward on each side of its middle line and extending its whole length, as shown by roo the dotted line H, Fig. 1. At the ends and on each side it has crow-feet I projecting, to give the machine suitable width of base to stand upon. The width of the space between the ribs I-I is represented by the lines J, Fig. 2, and extends outward from the lines K, Fig. 1. Between the lines K the width of this space is represented by the lines L, Fig. 2.

The two iiprights M are bolted to the ends ofthe base G with the bolts N. These uprights are connected at their upper ends by the beam O, the saine being bolted to the uprights with bolts P. At thelower edge of the connecting-beam O is a shelf, Q, which supports the microscopes l), the latter being attached to a slide or way, S.

T is a plain piece of cast-iron, attached to the base G by means of the shaft Y and boxes U Y. The boxes V are bolted to the flanges XV on the piece T, while the boxes U are bolted to the base G, as shown. These boxes are made in halves77 in the usual way, so they can be clamped snugly upon the shaft Y. To prevent any end motion of the hinged piece T, hardened-steel pieces X are put into the ends of the shaft Y, and abutting pieces Z are attached to bed G in boxes Z2, and held against the shaft by set-screws AV` To the swinging piece T are attached the head-pieces C, and D upon which are fitted the sliding tables E, and F,. Upon these tables rest the standards or scales G, and H, while being compared one with another. The head-piece G, is bolted firmly to the swinging piece T, and the head-piece D, has a vertical adjustment, which will be understood on ret crence to Figs. 1, 2, l, 10, and 11. It is attached to T by means of four bolts, J which pass through slotted holes in D, (the slots being sufiieiently long to allow the required vertical adjustment) and are screwed into T. J Fig. et, are worm-wheels passing through and their hubs fitting into slots in D more plainly Shown in Figs. l() and 1l. Right handed screws K, are fixed into the worin-wheels J and screw into' the bolt-stiids L which are fitted into T and bolted to 0,. Cavities M Fig. 11, are coicd into D as shown, so as to allow D, to move up and down the required distance without striking the studs L,. Two shafts, N, and 0 are fixed to D, by means of the bearings P,. To these shafts are fixed the hand-wheels Q the miter-wheels R and a righthand worin, S and a left-hand worin, T meshing into the woriii-wlieels J The miter-wlieel U, is fixed into the liand-wheel 'V and is supported by the stud NVV X, is ar link, which is thicker at one end than the other, and is suspended from the stud XV, between the hub of the hand-wheel V, and the nut Y,. By turning the hand-wheel V inotion will be imparted yto both the shafts N, and 0 and bot-h ends of the liead-pieee D, will be raised or lowered simultaneously and alike. By turning the link X, over so it will be suspended by its thin end, the niiter-wlieel U, may be drawn out and disengaged from the wheels 12 after which either end of the headpiece D, may be raised or lowered slightly and independently of each other by turning either of the hand-wheels Q,.

Fig. 17 shows more plainly the manner in which the tables E, and F, are fitted and fastened to the liead-picce C, and D,. A halfdovetail7 is formed at Z and against this the tables E, and F, are held by the clamps A2 and bolts B2 and G2. The bolt B2 is provided with a tail-nut, D2, so it can be conveniently tightened from the front side of the coniparator-the side to the left in Fig. 2. The

tables E, and F, are so fitted as to have their upper surfaces inclined sufficiently to bring them perpendicular to the axis of the microscopes when brought directly under the latter. The rear table, E is' provided with a screw, E2, and liand-wlieel F2, (shown in section in Fig. 1,) by means of which it maybe adjusted endwise. The means for adjusting the front table, F may be seen by referring to Figs. l, 2, 3, 5, 6, and 7, the saine being provided with two racks, G2, fastened to the bottom side of' the table F and pinions H2, connected with the hand-wheels l2 and J2, and fitted into the head-piece D,. For delicate adjustments the hand-wheel J2 has a V-groove turned into. it, and into this is fitted a slide, K2, Fig, 6,whieh may be adjusted to any part of the circumference of the wheel J2. Into this slide K2 is fit- Vted a lever, L2, of considerable length, by means of which the table F, may be moved `very slowly. The stud M., and clamp N2 serve as afastening to hold the ta-ble F, in a definite position. On the riglit-hand end of tlielieadpiece D, is fitted a stop, O2, which limits the motion of the table F,. This stop has a tongue, 12, on the lower side, fitting into a corresponding groove in the casting AD,. There are a number of these grooves at regular intervals, so the stop O2 can be moved to different positions, and thus regulate, in connection with the set-screw Q2, the amount of motion of the table F,. On the left hand a stop, R2, is bolted to the casting 1) and provided with the set-screw Q2 for adjustment. S2, T2, and U2 are steel plugs set into the table F, and the stop O2, to form hard abutting surfaces. The point of the sctsei'ew Q2 is also hardened. Y, is a clamp-screw for the purpose of tightening the screw Q2.

In using the comparator it will be necessary to swing the central. piece, T, upon its pivots V U, in order to bring the tables E, and F, and scales or standards H, and G, alternately under the microscopes R. To accomplish this, a hand-wheel, V2, is suitably fastened to the upright M on the left, Fig. 1, substantially as shown. A link, X2, is fastened at one end with a hinge-joint to castings Tand (3 and at the other end it is attached to a slide-block, Y2, which is adjustable diainet-rically in reference to the wheel V2, thus allowing a variation in the stroke or throw of the swinging parts. The clamp Z2 serves to clamp the handwlieel XV, in any desired position. For this IOO IIO

purpose the clamp Z2 is providedwithan index-point, A3, and the rim rof kthe wheelis graduated Von the side, as show-n in Fig. 2.

The miscroscopes R are mounted upon suit-- able frames, F3, which are clamped to the slide S by means of set-screws G3. y

Fig. 9 is a partial side view of the tables E, F1 and the standard G1, showing themanner of inserting thermometers Hw by means of which the temperature of the metal may be read at any time. I3 is a glass inclosing the thermometer in the cavity J rFhe cavity J., is partially filled with mercury surrounding the bulb 'of the thermometer to readily transmit any variation of temperature from the metal to the thermometer. j Fig. 8 is a top view of the standard G1, Fig. 9. Fig. 18 is a top View slide. F3 is a sliding frame, attached to the slide S. 7 is a cross-slide attachedto F3 and clamped by screw 3. Sis avertical slide, and is attached to slide 7. 0 It is adjusted by'screw 6, while 4 and 5 are screws that tighten slide 8; G3, screws that holdslide F3 firmly to slide of a microscope and Fig. 19 is a cross-vertical section through A B, Fig. 18. 14 is the micrometer-screw, and 2 is the clamp-screw, which secures the microscope to slide 8.

Fig. 20 is a rear section through line C D,

Fig. 19. It will be seen that by these slides and ways` the microscopes can be adjusted vertically, longitudinally, and transversely with great facility.

That the comparator may stop accurately at the same point each time it isswung, stops Bj., Fig. 2, are put into the uprights- M, at eachk end of the machine, and steel pieces 0 bolted to the frame, to form true and firm bearingsurfaces to come against the stops. The comparator is'swung back and forth by wheel WV, and brought gently against the stops B. When the comparatoris swung past the center, it will have atendency to move itself, and, should it be required, springs may be attached to the heads M, coming in contact with the comparator, and so arranged that itwill be nearly balanced in all positions. AHowever, it will be better for it to have suflicient tendency to move itself to insure its coming against the stops B3.

' rlhe comparator being swung bya slow crank motion, and coming against the stops at the dead-centers, there will be no perceptible shock when it comes in Contact with the stops.

To explain the operation of this comparator, a metallic bar, G1, representing a standard Vyard-measure, is clamped or votherwise proporly secured to table El, Figs. 2 and 15. This bar has two lines, AG and A traced upon-its surface, one near each end, the space betweenl the lines being a standard yard. .A bar, H1,

' to be lcompared to bar G1, .is Vsecured to table F1 in a similar manner, having linesBs and B, near the ends the same as bar G1, the distance between which is intended also to be a standard yard. The bars having been thus placedV and microscope BG over line AT and firmly clamped to slides S, Fig. 2. Then, after adjusting the cross-hairs of the micrometers t0 their respective lines, the tables areswung back and the bar H, brought under the microscopes, Fig. 16, and by means of the vertical adjustment of the head D the surface of the bar Hl is brought up to the face of the'microseopes, and by means of the end adjustment of the table F1, or by moving the bar H1, line BG is adjusted to the cross-hairs of microscope B, Fig. 16. After being thus arranged, thebars should be alternately brought under the microscopes several times and critically examinedto guard against errors in the adjustment of the micrometers. The process being thus completed. microscope B6 will show how the lengths of the two bars agree. To obtain the best re sults, the two bars should be ofthe same kind of ,the other half, and as two microscopes cannot be placed much nearer together than three inches, the inches and parts of inches can be tested, as described below. In comparing the feet, half-feet, and quarters ot' feet together, as Aabove indicated, the scale can be moved under the microscopes, or the microscopes may be clamped firmly together and moved over the scale; but the former method is considered preferable when the scale can be conveniently moved. j

Ihe following is one method of testing the smallest subdivisions of a scale. Fig. 5 is a top view of table F1, Fig. 2, and Fig. 6 is a front ele-- vat-ion of the same. A bar of metal, M5, having two lilies, N., and O1., at a distance apart nearly the same as the subdivisions to be tested, is firmly fastened on the left end of table F,. The scale K to be tested is clamped upon the table F1 by clamps 11 or secured in any of the known ways of doing such work. By means of screw Q2 and stop U2 the motion of the table F1 is limited, for convenience, to the distance between marks N, and O3 on bar M3.

To compare the space on the scale K3 from O to 1, to the space from O3 to N3 on bar MI., the table F1 is moved to the left against they stop-screw Q. Microscope Q3 is adjusted to line O on scale K3, and microscope P3 to line O3 on bar M3; then the table is moved to the right until microscope l?, coincides with line N3; and after moving the table back and forth Several times'and critically noting the adjust- IOO ment of the micrometers to avoid err'ors, the difference between thelength of the two spaces, if any, will be indicated by microscope Q3; then the table Fl is moved to the left, as before, against set-screw Q. and microscope Q,

is moved over and adjusted to mark 1, and microscope B., is adjusted to line 02,; then the table is moved to the right until microscope B, shall again coincide with line Ng and after moving back and forth several times, as before, to test the accuracy of the adjustment of the micrometers, the reading of microscope Q., over line 2 on the scale, will show how space from 1 to 2 on scale li, agrees with space from O,s to N3, and so on until all the spaces on K, shall have been tested. The screw-stops Q.l and U2 need not be depended upon for accuracy, but if they are made sufficiently strong there is no reason why they should not be. They should be made so as not to yield perceptibly to any pressure brought against them. Table Fl is moved up to stop U., by lever L2, which is made ot' a size that will bend sufficiently easy, and is so arranged that table F, will come in contact with stop U2 a little before the lever touches the rest M2, so that when the lever is brought down to the rest and secured by clamp N., it will be bent a little, as shown by the dottedlines. This spring of the lever serves to keep the table against stop U., always' with the same force. The table is held against set-screw Q in a similar manner and one lever may be used for both wheels I, and 1,. 1t will be seen that more than one microscope could be used to advantage on scale K, to test more than one space at a time,

One method of comparing end-measure with line-measure with this comparator is shown in Figs. 2, l2, and 18. The standard bar G having lines C, and 1) is secured to table E, by clamps Z, and ZV Upon the fronttable, Fl, is rigidly attached an abutting bar, Bh. S is a similar bar, placed against Rwand held in place by springs U and Vm )in J holding bar E in position. T is a wooden handle, by which the bar S, is moved to prevent the warmth of t-he hand from affecting its temperature. X, is an end-measure to be compared to the linemeasure standard G1. and is laid loosely upon the table F,. The comparator is then swung forward by wheel \V and the microscopes E, and Fw, are adjusted to the lines C, and D, on the standard G,. The comparator is then swung back` and, by means of vertical adjustment of head D1 and the longitudinal adjustment of table F mark H, on bar S,I is adjusted to microscope 15 and microscope B, is adj usted to mark G, on bar Bh. Then the comsecured to the table F1 that no pressure that will be brought against it will move it. Great pains must be t-aken to havethc abutting ends free from dust and lint, Src., before placing them together, which will need to be done with the utmost care. The end-measure having been thus carefully put in position, the comparatoiis swung back and marks H, and G, brought under microscopes F, and B and if line H, coincides with microscope F and line G, with microscope 13 the end-measure X agrees with standard G1. The extra microscope B, is used to detect any longitudinal movement of the bar Bil., or of the comparator, should such an accident happen. To guard against slight errors before considering the process completed, the comparator should be moved back and forth several times and the microscopes examined critically each time.

End-measure can be compared with linemeasure with a comparator having but one table, as shown by the following brief description, viz: Aline-measure, G1, an end-measure X, a fixed abutting bar, Rm and a movable abutting bar, Sm are placed on a table, as shown in Fig. 20% Bar S., is placed and held against bar Bp Microscope E, is placed and iirml y held over and adjusted to line H,. (Microscope B, maybe set over and adjusted to line G, at the option of the operator.) Then measuresG1 and X, and bar S, are arranged as shown in Fig. 2l. Line C, is adjusted to microscope E and microscope F, is set over and adjusted to line 1),. Then the articles are arranged, as shown in Fig. 22, when microscope F, will show the comparative lengths of the two measures. \Vhe11 short measures-say two feet and less-are to be compared, the abutting bar S, and miscroscope E, can be dispensed with, as shown in Figs. 23 and 24, the line-measure G, being made to perform the function of bar Sin addition toits own. Being arranged as shown in Fig. 23,1ine-measure G, is placed and held in contact with bar R31.

and microscope F, is placed over and adjusted to line 1),. Then line-measure G, is run back and end-measure X is placed between it and bar Bh, as shown in Fig. 24, and line-measure G, is pressed against bar X., suiiiciently to hold the abutting surfaces in contact when microscope F over line Cwill show how the measures agree, the line-measure G, having been run back the exact length ofend-measu1eX In testing measures of length,the most essential and, perhaps, the most difficult part of the operation is to bring the articles to be tested to a uniform temperature, and keep them so during the process, and when two kinds of metal are compared together, it is necessary to know the exact degree at which they are tested. The usual method of laying a thermometer on the scale which is to be tested, or on the table with it, is not suiiciently reliable therefore I embed a thermometer in the scale when it is thick enough, and also in the table of the comparator, Figs. S and 9, for the temperature of the table affects the scale, which IOO rests upon it, and nearly controls the temperature when the scale is thin. The thermometer lwill need to be as smallas possible when inserted into the table or scale, but it may be made of common size, and the bulb only inserted, as shown in Fig. 9, in which case a hole, D6, is drilled inthe piece and iilled with mercury, .and the bulb of thermometer H5, or the mercury can be taken out.

set in the hole, thelatter being packed around the thermometer to prevent the atmospheric air from affecting the mercury; and for that purpose a rubber ring, Z6, may be put around the thermometer, just lling the top of the hole. Vhen the thermometer is taken out, the hole may be stopped with a rubber plug, In a heavy standard, doubtless, it` would be more convenient to have the thermometer embedded in it. It is'obvious that the insertion of a thermometer into many other kinds of machinery would be of great advantage, as it would always indicate the exact temperature of the piece it 'is in. Y

In testing end-measures, the standard linemeasure may be the movable abutting bar S3' abutting bar, comparisons can be made with one microscope when a detective-microscope, Bl, is not used. Referring to the swinging of the comparator-tables, it will be seen that the accuracy of the comparisons will not depend upon the accuracy with which the tables are swung back and forth. As there Varaalways two microscopes used when the tablee swung, any movement longitudinally would be detected.

The tracer referred to above is not a part of the comparator, but is a small instrument for copying graduated measures, and is well known to all who are familiar with the art. It is constructed in various ways, has a cutter, and means for holding and operating the same, and generally carries a microscope. In using a tracer with my comparator, it would be attached to slide S on beam O, -on which it would be operated. The head-rest YB is a horizontal shelf, as shown in the drawings, but may be made in any convenient form for the operator t-o rest his head upon when looking through the microscopes. This support or head-rest may be a part of the beam O, or a separate piece, and fastened to it, and it may be made vertically adjustable. I preferably make the height of said rest so as to bring-the head of the operator in thev right position-when his head rests upon his hand and his hand upon the shelf O. I prefer to rest my forehead on :my left iist, the latter resting on the head-rest, leaving the right hand free for operating the -micrometer of the microscope. The benefit A o f this device is obvious, considering the great difficulty of holdingthe head sufficiently steady when making observations with microscopes of high power.

Having' fully described my improvement, what I claim, and desire'to secure vby Letters Patent, is.- v

1*., VFor testing measures of length, a comparator having, in combination with microscopes, separate tables or supports for said measures fixed to a swinging frame, substantially as described.

2. A comparator having, in combination with atable or tables, microscopes and a beam supporting the microscopes, a tracer, and head-rest, said beam being held by its ends and elevated above the tables, leaving the 'space under it open for the moving back 4and ing said table longitudinally, including lever L2, and stop-rest M2, substantially as described.

5.l A metallic bar or body having in it a mercury-well, and a thermometer embedded in said well, substantially as described, and for the purpose set forth.

6. For comparingmeasures of length, a comparator having a table or support for the articles to be compared, said table having in it a mercury-well, and a thermometer embedded in the well, substantially as described, and for the purpose set forth.

7 For comparing measures of length, a comparator having, in combination, a table or support for the measures, one or more microscopes, a guide or slide, S, running nearly parallelwith the table, a vertical guide, 8, and a vtransverse guide or slide, 7, by means of which i of the lines thereon, to coincide with the microscope cross-hairs; fourth, adjusting the cross-hairs of a second microscope to the other line of the line-measure, fifth, substituting for the line-measure an end-measure, abutting it against the iiXed bar, sixth, abutting the movable bar against the end of the end-measure; seventh, observing the line on the movable ybar through the second microscope, and noting the amount of divergence, if any, of the line from the cross-hairs of the microscope.

9. The following method of comparing lineal end-measure with lineal line-measure:

ICO

IIO

iirst, abutting the line-measure against aixed bar; second, adjusting a microscope to that line of the line-measure which is farthest from the fixed bar; third, inserting between the iixed'bar and the line-measure an end-measure; fourth, observing through the microscope that line on the line-measnre which is nearest to the fixed bar, and noting the divergence, if

any, of the line from the crosshairs ofthe mioroscopo.

10. For comparing end-measure with linemeasure, a comparator having, in combina tion, a table or support for the measures, two or more microscopes, and two abutting bars, substantially as described.

l1. For comparing end-measure with linemeasure, a comparator having,in combination, a table or support for the articles to be compared, one or more microscopes, and two SAML. DARLTXG.

XVitliesscs:

JACOB KETTNER, JOHN E. H nur., 

